Stop doing 20 of the same math problem

Blocked practice lies to you

Twenty subtraction problems in a row teach a child to stay in subtraction mode. They stop asking what the problem is. They just keep subtracting. That page can look excellent and still fall apart when a mixed worksheet shows up on Friday.

Doug Rohrer's work on interleaved math practice keeps finding the same pattern. Mixing problem types makes practice messier. Kids have to look at the problem and choose a method. On a later test, that extra decision pays off. In one study with fourth graders, Kelli Taylor and Rohrer found that mixed practice beat blocked practice the next day by a wide margin, even though the mixed group looked worse while they were practicing.

Spacing is the other half

Nicholas Cepeda, Harold Pashler, and colleagues reviewed hundreds of spacing comparisons. Cramming into one sitting helps tomorrow's quiz and fails the test you care about later. Spreading the same items across days is slower and more durable.

For homeschool math, that means today's new skill still belongs in Thursday's warm-up and next week's mixed set. A single long block of "we are doing fractions now" is a weak plan if those problems never return.

• Teach one type, then put two or three types on the same page.
• Bring last week's skill back for five problems before you start today's lesson.
• Expect more errors during mixed practice. That is the point.
• If they cannot tell which operation to use, they do not own the skill yet.

What this looks like on a Tuesday

After you teach two-digit subtraction, do not assign a full page of only that. Give four of those, three addition problems they already know, and two word problems that force a choice. Tomorrow, change the mix. The learner should never be able to complete the page on autopilot.

If mixed practice produces panic instead of thought, shrink the set. Four mixed problems with attention beat twenty blocked ones they can finish half asleep.